Architecture of the pontin/reptin complex, essential in the assembly of several macromolecular complexes.
Pontin and reptin belong to the AAA+ family, and they are essential for the structural integrity and catalytic activity of several chromatin remodeling complexes. They are also indispensable for the assembly of several ribonucleoprotein complexes, including telomerase. Here, we propose a structural model of the yeast pontin/reptin complex based on a cryo-electron microscopy reconstruction at 13 A. Pontin/reptin hetero-dodecamers were purified from in vivo assembled complexes forming a double ring. Two rings interact through flexible domains projecting from each hexamer, constituting an atypical asymmetric form of oligomerization. These flexible domains and the AAA+ cores reveal significant conformational changes when compared with the crystal structure of human pontin that generate enlarged channels. This structure of endogenously assembled pontin/reptin complexes is different than previously described structures, suggesting that pontin and reptin could acquire distinct structural states to regulate their broad functions as molecular motors and scaffolds for nucleic acids and proteins.
Torreira
Eva
E
Centro de Investigaciones Biológicas/Centre for Biological Research, Spanish National Research Council (CSIC), Ramiro de Maeztu, 9, 28040 Madrid, Spain.
Jha
Sudhakar
S
López-Blanco
José R
JR
Arias-Palomo
Ernesto
E
Chacón
Pablo
P
Cañas
Cristina
C
Ayora
Sylvia
S
Dutta
Anindya
A
Llorca
Oscar
O
D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism* / Q000502:physiology; D000255:Adenosine Triphosphate / Q000378:metabolism; D020285:Cryoelectron Microscopy; D004265:DNA Helicases / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism* / Q000502:physiology; D006868:Hydrolysis; D046911:Macromolecular Substances / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D008958:Models, Molecular; D020409:Molecular Motor Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology; D009696:Nucleic Acids / Q000378:metabolism; D020836:Protein Structure, Quaternary; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism* / Q000502:physiology; D014157:Transcription Factors
D046911:Macromolecular Substances; D020409:Molecular Motor Proteins; D009696:Nucleic Acids; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; C428198:RVB1 protein, S cerevisiae; C428199:RVB2 protein, S cerevisiae; D004265:DNA Helicases